1. Field of the Invention
The present invention relates to a semiconductor device. Further, the present invention relates to an electronic appliance mounted with the semiconductor devices.
Note that the semiconductor device in this specification indicates all the devices that can operate by utilizing semiconductor characteristics. For example, a power device, a display device including the power device, an integrated circuit including the power device, and the like are included in the category of the semiconductor device.
2. Description of the Related Art
A technique by which transistors are formed using semiconductor thin films formed over a substrate having an insulating surface has been attracting attention. As a semiconductor thin film that can be applied to the transistors, a silicon-based semiconductor is known, and as another material, an oxide semiconductor has attracted attention.
For example, disclosed is a transistor whose active layer is formed using an amorphous oxide containing indium (In), gallium (Ga), and zinc (Zn) and having an electron carrier concentration of lower than 1018/cm3 (see Patent Document 1).
[Reference]
[Patent Document]
    [Patent Document 1] Japanese Published Patent Application No. 2006-165528